1. Field of the Invention
The present invention pertains to a multi-directional mobile inspection system which may be used in a variety of applications including the inspection of turbine generator ("TG") stator baffle ducts.
2. Background Information
Frequently, it is necessary to perform visual and non-visual inspections in locations which are difficult, if not impossible, to access without disassembly of the apparatus which is being inspected. Under such conditions the cost, or complexity of apparatus disassembly, frequently limits the number of important inspections which are performed. One such area where inspection is difficult to perform is within TG stator ducts.
The TG stator ducts are located at the outside diameter of the stator bore and are tangentially disposed around the perimeter of the bore The cross-sectional area of each duct varies around the perimeter but at some points, the cross-section is only two inches in radial depth and ten inches in axial width. Length can be up to one-half the perimeter of the stator. Approximately a dozen ducts are located at equal spacing along the core. Their function is to introduce cold gas to, and remove hot gas from the hot and cold gas zones in the generator and there are up to seven zones in the generator.
Recently, several of these baffle ducts have failed causing a portion of the duct to fragment Such fragments frequently are blown across adjacent parallel rings causing rapid magnetic heating of the failed baffle duct fragment Such heating of the fragment then melts the electrical insulation of the rings which are in contact with the fragment causing two of the generator phases to fault The present method of inspecting baffle ducts is to perform a visual inspection of the accessible areas using a flashlight and mirror. This results in an inspection of only about ten percent of the duct The other ninety percent of the duct area is not inspected.
Accordingly, there exists a need for an inspection system for TG stator baffle ducts, and other hard to access apparatus, that can access a greater portion of a baffle duct.